Just the same as spewing water from the back of jets on a clear day can cause changes in the atmosphere and hence, modify the weather, by producing water vapour clouds.
NO THEY DON'T. The largest change in insolation ever measured (measuring a sky overcast by trails) involved less than a 2% change. But you lose the blue, of course.

Just look at the sky on a clear day when the jets are out spraying in criss-cross patterns.
Routes cross each other, and you are a simpleton. The stratosphere travels in a different direction from your prevailing wind, has an average speed of 50+mph. Crossing shuttle routes will produce a "grid" if the stratospheric layers they pass through approach saturation with water vapor. You cannot SEE the stratosphere, wet or dry. Grids can be made over your horizon and yet arrive overhead an hour or two later.

Soon, the long white streaks fan out into thin, but wide, white clouds.
All made out of 99.9994% pure water...

Take note as to what type of weather follows.
Watch my T-shirt: the persistent spreading contrail starts by being entrained in the aircraft's wing vortices. These are angled shallowly downwards such that by the time they have stopped spinning the trail is 200 miles behind and a thousand feet beneath the aircraft. Each vortex loop forms a serration in the trail up to two thousand feet deep. Each serration is actually cone-shaped, with a centre of larger ice particles falling fastest. The faster they fall, the faster they accrete ice, so it is a form of instability.
Normally before this happens the saturated layer has ceased to be the ambient layer, and the ice starts to evaporate again. If it makes it down through the tropopause then it will evaporate as it falls through the ever-warming air. This gives you the high leaden overcast - for it is usually at a certain narrow band of altitude (and temperature) everywhere that the ice particulates have finally sublimed to nothing. At that point, by the way, the seed particulates (soot and acids) are released for, in effect, re-use.
If layers have a LATERAL motion then a contrail will SHEAR in a cirrus-like manner - because, technically it IS a cirrus cloud, its only distinction being that of possessing a slightly-different granularity - of ICE.

Water vapor is an invisible GAS. When you observe a boiling kettle, the INVISIBLE gas emitted is water vapor. Further from the spout, where the "steam" is visible, it ISN'T "steam", but droplets of water suspended in air. A cloud.

There is no such thing as a "water vapor cloud". Water vapor IS steam. Steam at 1100C is 27.6% of a modern turbofan engine exhaust by weight.

Kindly explain to the forum, JazzRoc, in your opinioin, why non-passenger planes spew whatever it is they spew from the back of their planes on a clear day that begin as long white streaks, but ultimately end up fanning out into thin white, whispy clouds. What are they spewing? Why are they doing this? What is the purpose? Thanking you in advance, BA

You are lying, astroturfing, and skirting my questions once again.

You are a moderator here? You behavior needs moderating by someone truly responsible.

The answer to your questions is that they are just the natural results you get when you burn kerosine in the stratosphere.

This, FOR THE THIRD TIME IN THIS THREAD, is evidenced below in the following atmospheric science research papers.

Because you are hard of thinking, I'll translate it into simple terms.

For every yard of forward flight at cruise altitude a jumbo jet may produce thirty-five pounds of trail ice. It only depends on the water vapor content of the surrounding air. This ice evaporates back into the air when it has fallen to a height of 4-5 miles. Another forty years of continual expansion of air travel may take place before there is a significant effect on the weather.

That's it. Only a moron would fail to understand this.

“Contrail Formation and Persistence”contrail.html“Long lasting contrails like the ones observed usually occur in parts of the sky that have preexisting patches of cirrus clouds. Since the cirrus clouds are formed of ice crystals like the contrails, cirrus clouds in a region of the sky suggests supersaturation with respect to ice and sufficient heterogeneous nuclei for ice crystals to form. GOES-8 satellite photographs taken at approximately at the same time as the contrails were present show significant cirrus clouds around the Norman area providing the condition necessary for contrail persistence.”

S J Moss (1999). The Testing and Verification of Contrail Forecasts using Pilot Observations from Aircraft. Meteorological Applications, 6 , pp 193-200The testing and verification of contrail forecasts using pilot observations from“Recent research has shown that old forecasting techniques may not be wholly applicable to modern aircraft that now use more efficient engines. In order to compare the performance of both the old and new forecasting techniques a validation trial was carried out over a nine-month period in which RAF pilots reported when and where contrails did and did not occur.”

A Laboratory Study of Contrailshttp://ams.allenpress.com/archive/15...9-15-2-149.pdf“The existence of supercooled water at temperatures significantly colder than -40C is not a generally-accepted fact, but has been suspected by theorists for some time. Fig. 5 demonstrates that such supercooling of contrail condensate, whatever its purity, is possible.”

Contrail Observations over Southern and Eastern Asia in NOAA/AVHRR Data and Comparisons to Contrail Simulations in a GCM
Contrail Observations over Southern and Eastern Asia in NOAA/AVHRR Data and Comparisons to Contrail Simulations in a GCM - International Journal of Remote Sensing“400 NOAA-14 satellite scenes from four months of the year 1998 were analysed. Both regions show sufficient air traffic to produce an observable amount of contrails. Thus we are able to measure for the first time contrail frequencies in the tropics and compare it to a nearby mid latitudinal region. The annual average of the daily mean contrail cloud coverage is 0.13% for the Thailand region and about 0.25% for the Japan region. For both regions the contrail cover is largest during spring. The daily cycle shows surprisingly high contrail coverage during night in spite of lower air traffic densities during night time.”

Proceedings of the Aircraft Research Associationhttp://www.greenerbydesign.org.uk/re..._Challenge.pdf“Persistent contrails, which in time degenerate into cirrus cloud, only form in air which is saturated with respect to ice and the conditions for their formation and persistence are reasonably well understood. There’s no prospect of a technological fix for that. If you fly through an ice-saturated region in the atmosphere, you’ll produce a persistent contrail.”

BOTH these sites refer to the "Contrails to Cirrus" paper in their side menus, and BOTH have been offered you as links on this thread... they say "There's NONE so blind as those that don't wish to see"...

You stand out as useless. Why conduct an argument about a subject you neither read nor understand? Only a moron would do this.

So, why are they burning kerosene in the stratosphere?
To provide the forward THRUST for flight at constant altitude.

Yes. I am a moderator here. A super RESPONSIBLE moderator at that and, thus, the reason why I was APPOINTED as such.
As a moderator you should be setting a standard for the rules of debate. Unfortunately you break many of these rules. Why don't you learn what they are? It will make you a better person in spite of yourself.

According to you, my behavior is irresponsible because I question your logic. Oh, yeah, that's logical.
Science is the best of everyone's logic. You'll have to learn some of it to appreciate it. Its application to our everyday world has brought us out of the Dark Ages.

I don't get Stompk. On one hand, he's trying to be a conspiracy theorist, but on the other hand he's doing the complete opposite. Such as stating that contrails forming into clouds is a myth. Try looking up into the sky on a clear day when the jets are out spraying and you'll see for yourself that it ain't a myth that contrails form into clouds. The eye does not deceive.
The eye SEES, then the brain INTERPRETS. Correctly if it is "well-informed" (educated), incorrectly otherwise.

However, words do and the bunch of mumbo jumbo mathematical information that many of the members here supply us with so as to attempt to confuse our critical thinking and deductive reasoning capabilities.
Science ain't science without the mathematics. Only when you have quantified may you qualify. It makes you put your money where your mouth is. It's worth any effort to improve ones understanding of the way the world is. Information is only part of it. Comprehension is the other part, and that is where you're lacking. Come to think of it, you haven't got the correct information either: chemtrail websites are notoriously and consistently WRONG throughout their content. And, of course, there's your innumeracy...

It's called information overload and/or brain fry. Trust your instincts and not the BS they post. They want you to believe that they are intellectuals in the topic at hand so they copy and paste, but cannot explain anything in their own words.
The journey of three thousand miles begins with but a single step.
I always use my own words - as well as the words of people cleverer, wiser, or better-informed than I am.
Why digress into "intellectualism"? Why not stick to the topic? Perhaps you know too little to debate any further.

KennyWally said: Do you think, that this would actually be broadcast on the mass media teevee? you're kidding, right? For me, I didn't need no stinking math to tell me what I could see. But, nice job, FWIW. They'll only recognize fellow whores, who spin an agenda, truth tellers are not welcome.
You must be out of your mind. This place has a readership of three. Truth tellers are not present.

Good post, Wally. I don't need no stinkin' math to tell me what I see either.
Beauty is, as ever, in the eye of the beholder. Sorry, nose of the beholder. Down, boy (those darned instincts, eh?)!
Send me all your money and I will double it for you.

Excuse me, but I am the SUPER MODERATOR of this forum because I do set a standard for the rules of debate and, I don't break any of those rules regardless of what you think.
What are the rules of debate?

We're not talking about science.
Oh, yes, we are. Well I am. You're talking pseudoscience.

We're talking about how you said that my behavior was irresponsible because I question your logic.
Suggesting cloud-seeding is weather modification IS irresponsible of you. Especially when you won't concede that almost the whole of human activities ARE modifying the weather.

Try sticking with the topic instead of changing the subject. We're not out of the dark ages.
Two lies.
The eye sees the contrails/chemtrails, whatever you care to call them and the brain interprets them correctly.
No it doesn't. You believe that the trail materials are emitted by the engines, when 99.99% of the materials are precipitated out of and reabsorbed back into the air. THAT is a failure to interpret what you see.

However, words do and the bunch of mumbo jumbo mathematical information that many of the members here supply us with so as to attempt to confuse our critical thinking and deductive reasoning capabilities. I'm not lacking anywhere, but you are. Come to think of it, you haven't got the corect information for anything.
Strange you should say that, for I (with many others, of course) designed and tested blades for jet engines, running the motors within a supersonic wind tunnel built within a fir forest in Hampshire in the early sixties. Loads of meaningless mumbo-jumbo later, aircraft like the Harrier and the Concorde turned up out of the blue. It must have been the magic spell we cast.

Trust your instincts and not the BS they post.
Yes, hard-working successful people are full of bullshit. I get your drift.

They want you to believe that they are intellectuals in the topic at hand so they copy and paste, but cannot explain anything in their own words.
That looks sick every time I explain something, doesn't it?

All you have to do to check what I say is look it up in any library.

I digress into intellcutialism because that is where my brain resides and I always stick to the topic, but you don't. Obviously, you know too little to debate any further.
You can't even spell the word. I have forgotten more than you will ever know.

Truth tellers are present on this forum, but, you ain't one of them so I suggest you go away. This forum has a very large readership.
I am here for reasons nothing to do with you. No more lies, please.

There will be no money forthcoming. We know when someone is spewing BS and that would be you.
Your multiple personalities missed the joke?

So, why are they burning kerosene in the stratosphere?
To provide the forward THRUST for flight at constant altitude.

I don't get Stompk. On one hand, he's trying to be a conspiracy theorist, but on the other hand he's doing the complete opposite. Such as stating that contrails forming into clouds is a myth. Try looking up into the sky on a clear day when the jets are out spraying and you'll see for yourself that it ain't a myth that contrails form into clouds. The eye does not deceive.
The eye SEES, then the brain INTERPRETS. Correctly if it is "well-informed" (educated), incorrectly otherwise.

Natural contrails are rare, and never form into clouds. Chemically modified contrails, called Chemtrails, do form gray, disgusting clouds.